Switch Mode Power Supply(SMPS)DC-DC Converter

The demand for the management of power in telecom and computing equipment’s are getting advance with the development of power technology.In the power management of these applications,the main focus is on high efficiency and high power density.The electronics products are facing so many challenges to deliver high performance,while consuming less power.Due to all these crises different governmental agencies around the world have or looking to improve the efficiency of their products in their respective specifications.Using conventional hard switches converters topology it will be very difficult to achieve such standard of efficiency specification.Three resonant topologies are been investigated because of their low switching losses but unfortunately when designed with hold-up time requirement,none of them could provide significant improvement over PWM converters.One such topology is the LLC Resonant converter.LLC resonant converter can achieve both high efficiency and wide input voltage range because of its voltage gain characteristics.The LLC resonant topology allows for zero voltage switching of the main switches therefore it helps to minimize the switching losses and improve the efficiency.A complete design procedure of half bridge LLC resonant converter is discussed in this thesis.Using Saber,the result is presented for open loop controlled converter.The results shows that zero voltage switching is achieved which increase the efficiency and regulated output voltage is obtained.From the result it can be concluded,that a half bridge LLC resonant converter is successfully designed.Furthermore this thesis contains short introduction to the feed control system.We used three different types of compensator in the closed loop circuit.In power converters type 2 Compensator is widely used in the control loop but there are some cases where the phase lags of the power converter approach 180 degrees,thus in such cases we use type 3 compensator.Type 3 compensator phase plot going above zero degree at some frequencies,therefore it can provide the required phase boost to keep a reasonable phase margin.Type 3 compensator is further divide into two types.Type 3-A and Type 3-B,both of them are discussed in chapter 4 of the thesis and the design procedure of type 3-A and type 3-B compensator for power converters are presented.